1. Field of the Invention
This invention relates to a refrigerated air supply apparatus for a refrigerator, and more particularly a refrigerated air supply apparatus for providing refrigerated air forward and rearward from a rear wall of fresh food compartment and from a door respectively.
2. Description of Background Art
As is shown in FIG. 1, generally a refrigerator has a freezer compartment 10 and a fresh food compartment 20 partitioned by an insulation barrier 5. The compartments 10, 20 are defined by inner cases 12, 22, respectively surrounded by insulation 7 which is cased by an outer case 2. And a fan unit 4 which is for providing refrigerated air to both freezer compartment 10 and fresh food compartment 20 is located in an evaporating chamber 11 located at the rear of the freezer compartment 10. An evaporator 8 is also provided in the evaporating chamber 11 which evaporator 8 generates refrigerated air by heat exchange. The compartments 10, 20 are closed by doors 19, 29 which are hinged in front of the refrigerator. A plurality of shelves 27, which store the food to be cooled, are mounted horizontally in the fresh food compartment 20. And at the bottom of the fresh food compartment 10, a storage box 28 is slidably mounted to keep a kind of food such as vegetables or fruits in which its temperature is maintained cooler than the rest of the fresh food compartment 10. And the doors 19, 29 have door baskets 26 mounted at inner surfaces thereof. The doors 19, 29 may be formed integrally with the door liner.
Conventional refrigerated air circulation will be explained in view of FIG. 1. As refrigeration cycle drives, the refrigerated air is generated by the evaporator 8 in which working fluid or refrigerant flows. By the fan unit 4, a portion of the refrigerated air is directed to the freezer compartment 10, and the other portion of the refrigerated air is impinged on a grill 16 and then guided to fresh food duct 24 through a passage 15 defined by a shroud 14 and a grill 16. The refrigerated air in the fresh food duct 24 is blown out into the fresh food compartment 20 through a plurality of outlets 25 formed in the front surface thereof.
Refrigerated air supplied to fresh food compartment 20 via above-mentioned supply path, then moves forward and carries out heat exchanges with food stored on the respective shelves 27, thereby becoming relatively warmed air. The warmed air returns to the evaporating chamber 11 through a return duct 30 formed in the insulation barrier 5 with its inlet 31 adjacent to the door 29. And the warmed air returned to evaporating chamber 11 carries out heat exchanges with the evaporator 8, thereby becoming refrigerated air.
But the conventional refrigerated air circulation system has a number of shortcomings. First, it can not achieve uniform refrigerating effect in the whole fresh food compartment 20, since the refrigerated air is provided only one direction, forward, from the outlets 25 of fresh food duct 24. This means that the temperature of a portion adjacent to the outlets 25 is lower than that of a portion adjacent to the door 29. Therefore, food stored adjacent to the outlets 25 may be over-refrigerated while food stored adjacent to the door 29 is tend to be perishable due to the temperature difference. This problem is based on the fact that the refrigerated air is provided into the fresh food compartment 20 only one direction from the duct 24. Second, the temperature of the door-adjacent portion in the fresh food compartment 20 tends to be increased due to frequent opening of the door 29. It takes relatively longer time to decrease the temperature of door-adjacent portion than that of the portion adjacent to the fresh food duct 24. Third, it is difficult to keep the food fresh stored in the door baskets 26, due to inflow of warm air from outside when door opened.
An improved refrigerated air circulation system was described in U.S. Pat. No. 5,584,191 issued Dec. 17, 1996. According to the air circulation system, refrigerated air is blown out into fresh food compartment by either a cool air duct mounted at the corner of the fresh food compartment and door duct into which the refrigerated air is provided by a transmission duct mounted on a side wall respectively. The transmission duct is exposed to the interior of fresh food compartment and it only delivers refrigerated air which have been spouted in fresh food compartment through the cool air duct to the door duct. The air circulation system has still following problems although it improves homogeneous refrigerating effect by the refrigerated air spouted from the door duct.
A problem with the circulation system is that the transmission duct occupies a certain space in the fresh food compartment where food is stored so that the substantial storage space in fresh food compartment is restricted by the transmission duct.
Another problem is that the contour of the circulation system particularly contour of the transmission duct mounted in the side wall is not good in design.